import Adw
import Gtk

public extension ComboRow {
    /// Creates a ComboRow with static text, items, and selection behavior.
    ///
    /// Values are applied once when the widget mounts. The callback receives the selected item string.
    /// - Parameter title: The row title.
    /// - Parameter subtitle: The optional row subtitle.
    /// - Parameter items: The optional strings shown by the row.
    /// - Parameter onSelectedItem: The optional selection callback.
    @_disfavoredOverload
    init<S: StringProtocol>(_ title: S, subtitle: String? = nil, items: [String]? = nil, _ onSelectedItem: ((String) -> Void)? = nil) {
        self.init()
        self = self.title(String(title))
        if let subtitle { self = self.subtitle(subtitle) }
        if let items { self = self.comboItems(ComboItems(items), onSelectedItem: onSelectedItem) }
    }

    /// Creates a ComboRow whose text and items follow bindings.
    ///
    /// Binding modifiers update the widget in place and write widget changes back. Replacing the model resets selection to its first item.
    /// - Parameter title: The title binding.
    /// - Parameter subtitle: The optional subtitle binding.
    /// - Parameter items: The optional item-list binding.
    /// - Parameter onSelectedItem: The optional selection callback.
    init(_ title: Portico.Binding<String>, subtitle: Portico.Binding<String>? = nil, items: Portico.Binding<[String]>? = nil, _ onSelectedItem: ((String) -> Void)? = nil) {
        self.init()
        self = self.title(title)
        if let subtitle { self = self.subtitle(subtitle) }
        if let items {
            let holder = ComboItems(items.untrackedValue)
            self = self.comboItems(holder, onSelectedItem: onSelectedItem)
            self = self.appending { w, ctx in
                ctx.registry.add(items.subscribe { [w] values in
                    holder.values = values
                    w.setModel(model: Gtk.StringList(strings: values))
                })
            }
        }
    }

    /// Creates a ComboRow with live interpolated text values.
    ///
    /// Interpolated segments are re-evaluated when their dependencies change. The callback receives the selected item string.
    /// - Parameter title: The interpolated title.
    /// - Parameter subtitle: The optional interpolated subtitle.
    /// - Parameter items: The optional strings shown by the row.
    /// - Parameter onSelectedItem: The optional selection callback.
    init(_ title: Portico.InterpolatedText, subtitle: Portico.InterpolatedText? = nil, items: [String]? = nil, _ onSelectedItem: ((String) -> Void)? = nil) {
        self.init()
        self = self.title(title)
        if let subtitle { self = self.subtitle(subtitle) }
        if let items { self = self.comboItems(ComboItems(items), onSelectedItem: onSelectedItem) }
    }

}

/// Mutable item storage shared by a combo model and its selection callback.
@MainActor private final class ComboItems {
    var values: [String]

    init(_ values: [String]) {
        self.values = values
    }
}

private extension ComboRow {
    /// Installs a string model and reports valid selection changes.
    ///
    /// Selection positions that are invalid or outside the current item list are ignored.
    func comboItems(_ items: ComboItems, onSelectedItem: ((String) -> Void)?) -> Self {
        var view = appending { w, _ in
            w.setModel(model: Gtk.StringList(strings: items.values))
        }
        guard let onSelectedItem else { return view }
        view = view.appending { w, ctx in
            var last = w.getSelected()
            ctx.registry.add(w.connectNotify(detail: nil) { [w] _, _ in
                let position = w.getSelected()
                guard position != last else { return }
                last = position
                guard position != UInt32.max, Int(position) < items.values.count else { return }
                onSelectedItem(items.values[Int(position)])
            })
        }
        return view
    }
}